1. Field of the Invention
The present invention relates to a gas mixing system for enriching a flow of one gas with flow of another gas, with the combination and mixing of the gas flows being conducted so as to maintain a relatively constant percentage of the two gases in the resultant flow. The system of the present invention is particularly well suited for use in enriching a flow of pressurized combustion air with a flow of oxygen.
2. Prior Art
It is known to supply flows of pressurized gaseous fuel and combustion air to a gaseous fuel burner, and to adjust the rates of flow of gaseous fuel and combustion air to effect an efficient burning of the fuel while generating a desired level of heat energy output. The heat energy output of the burner typically is controlled by regulating the flow rate at which gaseous fuel is delivered to the burner. The combustion efficiency of the burner typically is maximized by regulating the rate of flow of combustion air to the burner so that the ratio of gaseous fuel to combustion air that is delivered to the burner is within a desired range.
In conventional practice, a flow of so-called "combustion air" is provided by using a fan or blower to introduce a flow of ambient air into a supply line and to effect its flow through the supply line to the burner. A movable member called a "damper" is installed in the supply line to provide a means for adjustably controlling the rate of flow of the combustion air.
Proposals have been made to enhance the combustion efficiency of gaseous fuel burners by enriching their combustion air flows with oxygen. To the extent that such proposals have called for the use of membrane or diaphragm operated valving elements to control the relative flow rates of oxygen and combustion air that are delivered to a gaseous fuel burner, such proposals have characteristically suffered from a number of drawbacks. By way of example, many such proposals utilize membranes or diaphragms that are deployed such that, if ruptured, oxygen is permitted to flow where it should not. In some cases, a ruptured diaphragm can ermit oxygen to mix undesirably with another gas, generating a dangerously explosive mixture. In other cases, a ruptured diaphragm can permit oxygen to be ducted at an undesirably high rate of flow to a burner, causing damage and/or creating a danger.
A further drawback of many prior proposals resides in their failure to provide a means for properly controlling the flow rate of one gas to a mixing location in accordance with the flow rate of another gas to the mixing location. Still other drawbacks reside in the undue complexity of the valving components that have been proposed, their attendant cost, and/or the assembly and repair difficulties they present.